Method of making laminated hybrid ceramic matrix composites

Abstract

A method for producing a laminated ceramic composite article with improved transverse and interlaminer shear strength. The method includes the steps of forming a laminated preform by interlaminating toughened green ceramic matrix layers which include a randomly oriented toughening phase with green layers of aligned fiber-reinforced ceramic matrix material and thereafter forming the ceramic composite article from the laminated preform.

I claim: 
     
       1. A method for improving the transverse strength and interlaminar shear strength of a laminar fiber-reinforced ceramic matrix composite article incorporating layers of fiber-reinforced ceramic material which comprises introducing into a laminated preform for the article, in planes parallel with planes of alignment of reinforcing fibers in the layers of fiber-reinforced ceramic, interlayers of toughened ceramic matrix material comprising a randomly oriented toughening phase comprising inorganic whiskers or chopped fibers, said interlayers of toughened ceramic matrix material being introduced by interlaminating green toughened ceramic matrix layers with green layers of fiber-reinforced ceramic matrix material to provide the laminated preform for the article, and then forming said article from said laminated preform. 
     
     
       2. A method in accordance with claim 1 wherein the ceramic matrix material in the layers of fiber-reinforced ceramic is substantially free of inorganic whiskers and chopped fibers. 
     
     
       3. A method in accordance with claim 1 wherein the toughened ceramic matrix layers are provided as a combination of interior and surfacing interlayers. 
     
     
       4. A method in accordance with claim 1 wherein the ceramic matrix materials provided in the fiber-reinforced ceramic layers and toughened ceramic matrix layers are of the same composition and structure. 
     
     
       5. A method in accordance with claim 1 wherein the inorganic whiskers or chopped fibers provided in the toughened ceramic matrix layers consist essentially of silicon carbide or silicon oxycarbide. 
     
     
       6. A method in accordance with claim 1 wherein the ceramic matrix material provided in the fiber-reinforced ceramic layers and toughened ceramic matrix layers is an alkaline earth aluminosilicate glass-ceramic matrix material. 
     
     
       7. A method in accordance with claim 1 wherein the toughened ceramic matrix interlayers are introduced into the composite as thin sheets of green ceramic matrix material comprising chopped fibers or whiskers. 
     
     
       8. A method in accordance with claim 1 wherein the toughened ceramic matrix interlayers are introduced into the composite as coatings of green ceramic matrix material on green layers of fiber-reinforced ceramic matrix material.